p018.hs

{- 
 - Solution to Project Euler problem 18
 - By Nayuki Minase
 - 
 - http://nayuki.eigenstate.org/page/project-euler-solutions
 - https://github.com/nayuki/Project-Euler-solutions
 -}


main = putStrLn (show ans)
ans = maxPath 0 0

maxPath i j = (triangle !! i !! j) +
	(if i + 1 < length triangle
		then max (maxPath (i + 1) j) (maxPath (i + 1) (j + 1))
		else 0)

triangle = [
	[75],
	[95,64],
	[17,47,82],
	[18,35,87,10],
	[20,04,82,47,65],
	[19,01,23,75,03,34],
	[88,02,77,73,07,63,67],
	[99,65,04,28,06,16,70,92],
	[41,41,26,56,83,40,80,70,33],
	[41,48,72,33,47,32,37,16,94,29],
	[53,71,44,65,25,43,91,52,97,51,14],
	[70,11,33,28,77,73,17,78,39,68,17,57],
	[91,71,52,38,17,14,91,43,58,50,27,29,48],
	[63,66,04,68,89,53,67,30,73,16,69,87,40,31],
	[04,62,98,27,23, 9,70,98,73,93,38,53,60,04,23]]